Do Spider Beetles Have Wings? Unraveling the Mystery

Spider beetles are common pests found in stored products, but their physical appearance may cause confusion. These insects are two to five mm long, oval or cylindrical, long-legged, and brown in color with a superficial resemblance to spiders, hence their name source.

While many insects have wings, spider beetles possess a unique structure. Their first pair of wings are hardened and thickened, serving as a protective shield for the fragile flying wings tucked underneath source. This Latin name for this order, Coleoptera, translates to “folded wing,” which provides a hint about their ability to fly.

What Are Spider Beetles

Size and Appearance

Spider beetles are small household pests, typically measuring between two to five millimeters in length. They have an oval or cylindrical body and are brown in color. These insects have long legs, giving them a superficial resemblance to spiders, hence their name.

Description

Often infesting stored products, spider beetles are common and widespread across the United States. However, they are not as abundant nor well-known as other household pests such as ants and cockroaches. Their appearance may cause alarm, but they are generally considered a nuisance and not harmful.

Notes

  • Spider beetles belong to a group of insects called Coleoptera.
  • Several species of spider beetles exist in the U.S.
  • They are more commonly found in dark, secluded areas like basements and attics.

In comparison to other common household pests, spider beetles have some key distinctions:

Feature Spider Beetle Cockroach
Size 2-5mm 10-50mm
Body Shape Oval Flat
Color Brown Brown
Legs Long Short
Infestation Risk Low High

While spider beetles may be an unwelcome sight, their presence typically does not pose the same level of threat as an infestation of other, more destructive household pests. If encountered, it is important to identify and remove any infested stored products to prevent further infestation.

Physical Attributes and Abilities

Do Spider Beetles Have Wings

Yes, spider beetles have wings, but they are usually hidden and not used for flight. Their wings are primarily for protecting the beetle’s delicate abdomen.

Example:

  • Featherwing beetles have wings that are folded out of sight under their body, which helps them float like dandelion seeds in the air 1.

Other Body Features

Spider beetles are known for their unique body features. Some of their prominent characteristics include:

  • Long legs2
  • Oval or cylindrical body shape2
  • Brown color2
  • Range in size from 2-5 mm long2

In the development stage, spider beetle larvae have a segmented body with three pairs of legs near the head and a pair of leg-like appendages near the back.

Comparison Table:

Spider Beetles Other Beetles
Long legs Shorter legs
Oval/cylindrical body Varied shapes
Brown color Varied colors
Mostly 2-5 mm long Varied sizes

Now that we understand the physical attributes, spider beetles have unique features such as wings that are not used for flying and long legs that resemble spiders. Keep in mind these features can vary depending on the species.

Behavior and Habitat

Habits and Diet

Spider beetles are not as well-known as other household pests, but they do infest stored products in various households across the U.S 1. They are known to be:

  • Oval or cylindrical
  • Long-legged
  • Brown in color

These tiny insects, which measure between two to five millimeters in length, are often mistaken for spiders because of their superficial resemblance 1. One of their peculiar habits involves playing dead when disturbed, similar to certain spiders. The primary food source for these beetles is typically found in stored products like grains, cereals, or even dead insects.

Preferred Living Conditions

While preferring a habitat with an ample food source, spider beetles can also be found in other areas such as ceilings or any hard-to-reach places. Since they’re so adaptable, they can thrive in numerous environments. However, these beetles don’t spin webs like spiders do2. Their living requirements can be summarized as:

  • Access to stored products (food source)
  • Concealed or hard-to-reach areas
  • Ability to avoid predators by playing dead
Features Spiders Spider Beetles
Preferred Habitat Various environments Stored products, concealed spaces
Webs Yes No
Playing Dead Some species Yes
Legs 8 6

Life Cycle and Development

From Larvae to Adult

Spider beetles undergo a complete metamorphosis, consisting of four life stages: egg, larva, pupa, and adult. The larvae hatch from eggs and feed on various organic materials, eventually spinning cocoons to transform into pupae. Within these cocoons, they undergo the transition to adulthood.

Adult spider beetles have wings but are generally poor fliers. Their life cycle can take anywhere from a few months to over a year, depending on environmental conditions and food availability.

Signs of Spider Beetle Infestation

  • Presence of tiny, round fecal pellets
  • Damaged stored goods (grains, cereals, pet food)
  • Sightings of live or dead beetles
  • Shed skins or cocoons from the pupal stage

Comparison Table

Spider Beetle Other Common Beetles
Poor fliers Can fly long distances
Infest stored goods Typically feed on plants or wood
Small and reddish-brown Vary in size and color
Complete metamorphosis Varies by species

Identifying Spider Beetles

Visual Clues

Spider beetles are small insects, usually two to five mm long, oval or cylindrical, with long legs and generally brown in color. Their appearance can be confusing, as some species resemble spiders, hence their common name.

Preventing Mistaken Identity

To correctly identify spider beetles, it’s important to know some of their distinguishing features:

  • Long legs: Longer than other beetles, giving them a “spider-like” appearance.
  • Size: They are generally smaller than most other beetles, ranging from 2-5mm in length.
  • Color: Mostly brown, but some species may display variations in color.

Compare spider beetles to some other common insects like ladybugs or milkweed bugs that have their unique features:

Insect Size Color Shape
Ladybugs 1/4 – 3/8″ long Black to pink, yellow, or red Round or oval and convex
Milkweed Bugs Large – ¾” long Orange to reddish-orange Elongated and oval
Spider Beetles 2-5mm long Brown Oval or cylindrical

Remember to consider these visual clues and comparisons when identifying spider beetles to avoid misconceptions with other insects.

Footnotes

  1. https://entnemdept.ufl.edu/creatures/misc/beetles/featherwing_beetles.htm 2 3

  2. https://hortnews.extension.iastate.edu/spider-beetle 2 3 4 5

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Spider Beetle

 

Slow moving, tick-like bug
December 23, 2009
Hi bug people!
I have continuously seen these bugs in my bathroom, usually on the floor. I have never seen them anywhere else in my apartment. At first I thought they were ticks, but they crush very easily, and are round but don’t appear to be filled with blood. They move very slowly and the one I took a picture of was also moving very cautiously, exploring everything with its antennae. Not sure if this is normal, but when I used a flash, the bug appeared reddish (3rd photo). Otherwise, it appears black. It is also very very small, maybe about 1/2 cm. I’d really like to ID this bug to make sure it’s not posing any kind of risk to me by being there! Thanks in advance!
EG
Queens, NY

Spider Beetle
Spider Beetle

Dear EG,
This is a Spider Beetle, Gibbium aequinoctiale, a common pest of stored foods.  The origin of the beetle is unknown as it now has a cosmopolitan distribution.  Though you are finding them in the bathroom, unless you also store food there, you should look for the infestation in the kitchen.

Letter 2 – Spider Beetle

 

Hi,
I have found these guys a couple of times in my bathroom and was wondering what they were.
Sebastian Sparenga

Hi Sebastian,
What a detailed photo of a Spider Beetle from the genus Mezium. They are household pests. These tiny beetles will infest grain as well as exotic substances like cayenne, tobacco and opium. We doubt that you have an opium stash in your bathroom, but perhaps they are feasting on pet food, or shudder, the dead remains of an animal in the wall. Occasionally they will even eat woolens and other non-synthetic fibers.

Expert Update: (05/22/2008) spider beetle errors
Dear Bugman,
I believe I had written earlier when looking at many of the spider beetle pictures. Almost all of the shiny brown, globular body, images are of Gibbium aequinoctiale and not Mezium species. There is a combined 2 image photo (finger and beetle & 2 beetles) of Mezium : the answer was posted by Eric Eaton, I believe. Gibbium species do not have a velvety covering on the thorax, Mezium species do. You should correct your website postings so people will have a better idea of what they have been finding. Best regards,
Lou
Louis N. Sorkin, B.C.E.
Entomology Section
Division of Invertebrate Zoology
American Museum of Natural History
New York

Dear Lou,
Thanks so much for resending this vital correction to our website. We really appreciate your expertise on this. We sincerely hope that addressing you with such familiarity doesn’t detract from your professional status.

Letter 3 – Spider Beetle

 

Last resort
I have been a faithful, daily reader for some time now and really enjoy your website. I have also been trying to identify these little critters but can’t seem to find them on your website. I live in St. Louis, they like my bathroom and at any given time there are 3 or 4 of them hanging around. They appear to have only 6 legs but are the size of a mite, maybe 2 mm. Please tell me they are nice bugs. They are so cute I don’t have to heart to kick them out.
Teresa Spitz
St. Louis, MO

Hi Teresa,
Granted, Spider Beetles in the genus Mezium are cute, but they are nonetheless, household pests. These tiny beetles will infest grain as well as exotic substances like cayenne, tobacco and opium. We doubt that you have an opium stash in your bathroom, but perhaps they are feasting on pet food, or shudder, the dead remains of an animal in the wall. Occasionally they will even eat woolens and other non-synthetic fibers. You could have found images of Spider Beetles from previous readers on our Pantry Beetle page.

Expert Update: (05/22/2008) spider beetle errors
Dear Bugman,
I believe I had written earlier when looking at many of the spider beetle pictures. Almost all of the shiny brown, globular body, images are of Gibbium aequinoctiale and not Mezium species. There is a combined 2 image photo (finger and beetle & 2 beetles) of Mezium : the answer was posted by Eric Eaton, I believe. Gibbium species do not have a velvety covering on the thorax, Mezium species do. You should correct your website postings so people will have a better idea of what they have been finding. Best regards,
Lou
Louis N. Sorkin, B.C.E.
Entomology Section
Division of Invertebrate Zoology
American Museum of Natural History
New York

Dear Lou,
Thanks so much for resending this vital correction to our website. We really appreciate your expertise on this. We sincerely hope that addressing you with such familiarity doesn’t detract from your professional status.

Letter 4 – Spider Beetle

 

house bugs needed to be identified–couldn’t find it in your website and others
Dear Sir/Madam,
We have seen these bugs in our home for two years. We live in an one family house. They seem to come down from the attic above. First we spotted them in the light-cover on our ceiling. We cover our ceiling lights with milky-colored plastic cover. The bodies of these bugs are collected at the bottom of the cover, and some of them were still alive. It seems that they were trying to reach the light, and die there, then fall onto the cover base. Sometimes we see them in our bathtub, trying to get some drink. They are very small, about 1/8 to 1/6 of an inch in width, not including legs and antenna. These images were caught while one of them is crawling on the ceiling. We don’t know what these bugs are feeding on. Could you please help us to identify these bugs?
Thank you very much!
Sincerely,
Hsiling

Hi Hsiling,
You have Spider Beetles from the genus Mezium. They can be found worldwide where grain is stored. They also feed upon dried remains of animals, woolens and other non-synthetic textiles. You will find more images and information on our Pantry Beetle page.

Expert Update: (05/22/2008) spider beetle errors
Dear Bugman,
I believe I had written earlier when looking at many of the spider beetle pictures. Almost all of the shiny brown, globular body, images are of Gibbium aequinoctiale and not Mezium species. There is a combined 2 image photo (finger and beetle & 2 beetles) of Mezium : the answer was posted by Eric Eaton, I believe. Gibbium species do not have a velvety covering on the thorax, Mezium species do. You should correct your website postings so people will have a better idea of what they have been finding. Best regards,
Lou
Louis N. Sorkin, B.C.E.
Entomology Section
Division of Invertebrate Zoology
American Museum of Natural History
New York

Dear Lou,
Thanks so much for resending this vital correction to our website. We really appreciate your expertise on this. We sincerely hope that addressing you with such familiarity doesn’t detract from your professional status.

Letter 5 – Spider Beetle

 

bugs from home
Please help…
My wife was cleaning the other day and found these two bugs in some dust balls under our bed as well as in our kitchen cabinets and drawers. We tried looking online but can’t find anything that looks like these two guys – we’re wondering if they aren’t babies of something else. We’re not sure what to do about them or even where they came from. Thanks for your help,
Tom

Hi Tom,
It is difficult to be certain with your photo.

Update: (10/21/2005)
Hi, The insect pictured here copied from WTB is a spider beetle. It is a bead like insect often associated with rodent infestations. I managed to find your site when pulling up pictures of “lawn shrimp” to show an employee.
Doug Seemann , BCE
Board Certified Entomologist
San Diego County

Authors

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  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

6 thoughts on “Do Spider Beetles Have Wings? Unraveling the Mystery”

  1. i recently came across this in my brooklyn NY apt….this was in my bathtub, very tiny, .. but mine are slow, (maybe because the tub was cold ?).. i see them only once and awhile.
    they are very tiny, …. i dont see pinchers, like the pseudoscorpion, ..

    Reply
  2. I probably have spider beetles. They are the dice of a tick or smaller. Do not move for days at a time. Looks like a bit of dirt but smear when they are crushed. They are in my powder room and along the crevice where carpet meets the woodwork under my living room windows. I also see some in the master bath on the floor. I am in a townhouse on a slab send I have two cats.

    Reply

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